The Two Torahs

Our Rabbis taught: There was an incident with a certain gentile who came before Shammai. He said to him: How many Torahs do you have? He said to him: Two, the Written Torah and the Oral Torah. He said to him: As for the Written one, I believe you, but as for the Oral one, I do not believe you. Convert me on the condition that you teach me only the Written Torah. He rebuked him and drove him out in reproach. He came before Hillel, who converted him. On the first day Hillel said to him: Aleph, bet, gimmel, dalet. The next day he reversed them for him. He said to him: But yesterday you did not tell me thus! He said to him: Did you not rely upon me for that? For the Oral Torah too, rely upon me.